Circadian rhythms are your body’s built-in 24-hour timing system, coordinating when you feel awake or sleepy, how you digest food, how your hormones behave, and when your cells prioritise repair. You can think of it as an internal operating schedule that keeps key functions running in the right sequence. The main “master clock” in the brain is primarily set by light exposure, especially morning daylight, while “peripheral clocks” exist throughout the body in organs and tissues such as the gut, liver, immune system and skin. When these clocks are aligned, the body tends to run more efficiently with steadier energy, better mood, more stable appetite, improved digestion, and more predictable skin behaviour. When they are misaligned — for example through late nights, inconsistent wake times, bright evening light, irregular meals, or frequent travel across time zones — the system becomes desynchronised, which can increase stress signalling and inflammation.
For skin health, circadian rhythms matter because skin follows its own day–night pattern. During the day, skin is in defence mode, managing UV exposure, pollution, oxidative stress and environmental triggers, while at night it shifts into repair mode, focusing more on barrier recovery, hydration balance, and the processes involved in cellular repair. When sleep timing is inconsistent or evenings are overly stimulating and bright, skin can become more reactive and dehydrated, redness can flare more easily, healing can slow after breakouts or treatments, and the complexion can look duller with more puffiness or under-eye darkness. In clinic terms, circadian alignment becomes a performance lever: clients often tolerate active skincare better, recover more predictably, and see steadier progress when sleep and daily rhythms are stable.
The biggest practical levers for supporting circadian rhythms are surprisingly simple. A consistent wake time anchors the system more powerfully than chasing a perfect bedtime, and getting outside light in the first hour after waking helps set the master clock for the day. In the evening, lowering light levels and reducing screen brightness supports melatonin release and prepares the body for sleep. Keeping meals within a reasonably consistent window and avoiding very late, heavy meals can help synchronise the gut and liver clocks, while exercise earlier in the day tends to be more rhythm-friendly for many people than late, high-intensity training. From a skincare point of view, it also makes strategic sense to match routines to the skin’s rhythm: antioxidants and SPF in the morning to support daytime defence, and barrier repair and targeted actives in the evening to support night-time recovery.
Circadian rhythms impact the skin because they dictate when the skin is in defence mode versus repair mode, and that timing influences barrier strength, hydration, inflammation, oil regulation, pigmentation activity, and how well the skin recovers after treatments. In the day, skin is geared towards protection from UV, pollution and oxidative stress, so the barrier has to hold steady and the immune system stays on alert. At night, the skin’s priorities shift towards repair: replenishing moisture, restoring the barrier lipids, calming inflammation, and supporting the cellular processes involved in recovery. When your rhythm is aligned and sleep is consistent, skin tends to look clearer, calmer and brighter because repair is actually getting time to happen; when rhythms are disrupted, the skin stays in a semi-stressed state and results become harder to sustain.
A disrupted circadian rhythm commonly shows up as increased sensitivity and redness, because inflammatory signalling rises and the barrier becomes less resilient. You’ll often notice products stinging that previously felt fine, reactive flushing, or a persistent “tight” feeling, particularly in colder months or during stressful periods. At the same time, transepidermal water loss can increase, meaning the skin loses hydration more easily overnight and can look dehydrated, flaky, or rough even when moisturiser is being used. This is one reason clients feel like they’re “doing everything right” but still can’t hold hydration or glow.
Circadian disruption can also drive breakouts and congestion. Poor sleep and misaligned rhythms often destabilise cortisol and insulin regulation, which can increase inflammation and influence oil production and keratinisation. Clinically, this looks like more jawline congestion, slower-healing blemishes, and a cycle of flare-ups that doesn’t fully settle. On top of that, healing is slower, so post-blemish marks hang around longer and the skin can look more uneven for longer stretches.
Pigmentation is another area where timing matters. When sleep is poor or rhythms are inconsistent, inflammatory load increases and melanocyte activity can become more reactive, which means pigmentation is more likely to darken after irritation, breakouts, or aggressive exfoliation. This is particularly relevant for clients prone to melasma or post-inflammatory hyperpigmentation, where “overdoing it” plus poor recovery can become a repeat trigger. In parallel, oxidative stress rises with disrupted sleep, which is a known accelerator of visible ageing and uneven tone.
From an ageing and results perspective, circadian misalignment can undermine collagen maintenance over time by keeping the body in a higher-stress, higher-inflammation state and reducing the efficiency of night-time repair. Practically, clients often see this as dullness, reduced firmness, more pronounced fine lines, and slower progress from treatment plans. In-clinic, it can also mean heightened reactivity after peels or devices, longer redness, and a need to prioritise barrier-first protocols before pushing corrective work.
The strategic takeaway is that circadian alignment improves skin’s “return on investment” across everything you do — skincare, treatments, nutrition and lifestyle. When sleep and daily rhythm stabilise, skin tolerates active ingredients better, barrier function strengthens, inflammation calms, pigmentation becomes easier to control, and results from professional treatments tend to land faster and hold longer.
Natural daylight is one of the most powerful “master switches” you can use to stabilise circadian rhythms, because light is the primary signal that tells the brain it’s daytime. When that signal is strong and early, your body can run a cleaner daily cycle: cortisol rises when it should (for alertness), melatonin is suppressed during the day (so you feel awake), and then melatonin is released at the right time later that night (so you feel sleepy). In practical terms, morning daylight improves sleep timing, sleep quality, energy, mood stability, appetite regulation and stress resilience — all of which cascade into better inflammation control and more predictable skin behaviour.
Early morning daylight matters more than “daylight at any time” because circadian biology is especially sensitive to light in the first part of the day. That early light exposure acts like a time-stamp that anchors your internal clock, helping the body know when to start the day’s hormonal sequence. It supports a healthier cortisol rhythm (higher in the morning, lower at night), which is important for reducing stress-driven skin flare-ups and helping the barrier recover properly. It also makes it easier to feel sleepy at a reasonable hour because your body has a clearer “day begun” signal, which helps the brain initiate the evening wind-down sequence later.
From a skin and wellness performance lens, early daylight has a knock-on effect: better sleep means lower inflammatory signalling, stronger barrier integrity, steadier oil regulation and faster recovery from breakouts or treatments. Clients often notice that when they prioritise morning light consistently, skin becomes less reactive, hydration holds better, and they experience fewer “mystery flare-ups” driven by stress and fatigue. It’s not that daylight directly “treats” the skin; it optimises the physiology that determines whether skin can repair, calm and respond to skincare predictably.
The operational guidance is simple and realistic: aim to get outside within the first hour of waking for 10–20 minutes of natural daylight, even on cloudy Irish mornings, and ideally without sunglasses for at least part of that time (while still being sensible and not staring into bright sun). A short walk, standing in the garden, or even a coffee at the door counts. If you can’t get out early, sitting near a bright window helps, but outdoor light is far stronger and more effective. The key is consistency — because circadian rhythm is a compounding system: small daily inputs create big stability over time.
Infrared (Heat) and Skin Ageing: What It Does, What It Doesn’t, and How to Protect Your Results
Infrared (IR) is the “heat” portion of sunlight, and it represents a significant part of the solar energy that reaches us at ground level. The band most discussed in skin ageing is infrared-A (IR-A, roughly 760–1,400 nm) because it can penetrate beyond the surface into deeper skin layers where collagen and elastin sit.
Unlike UV, infrared doesn’t “burn” the skin in the same way, but research suggests IR-A can still contribute to photoageing pathways by increasing oxidative stress (free radical production) and triggering signals linked with collagen breakdown. In human skin studies, physiologically relevant IR-A exposure has been associated with increased MMP-1 (a collagen-degrading enzyme) in the dermis and measurable decreases in skin antioxidant levels, which matters because lower antioxidant reserves reduce the skin’s ability to buffer everyday environmental stress.
A second, very practical mechanism is heat. IR converts to heat in the skin, and repeated heat stress can amplify inflammation and contribute to changes seen in photoaged skin, including disruption in the dermal environment. This is why “heat exposure” often shows up clinically as more redness, reactivity, and a feeling that skin is harder to keep calm and hydrated — particularly in clients already prone to inflammation.
Myth vs reality
Myth: SPF covers everything, including infrared. SPF ratings relate to UV protection. Traditional sunscreen testing and labelling are UV-focused, so IR/heat management is usually a layered strategy rather than a single-number solution.
Myth: Infrared is always bad. Dose and intensity matter. Near-infrared and red light are also used therapeutically in controlled settings (photobiomodulation), where specific parameters are chosen to support repair and reduce inflammation. That’s a very different exposure profile from prolonged, uncontrolled solar IR/heat loading.
Reality: Infrared is a risk amplifier for certain skin concerns.” For clients managing melasma, persistent redness, post-inflammatory marks, or a reactive barrier, heat and IR exposure can be the factor that keeps the skin in a more inflammatory, pigment-reactive state — even when the skincare routine is excellent.
What this means for melasma and redness treatment planning
If you’re pigmentation-prone (especially melasma) or redness-prone, we treat heat/IR management as part of your overall risk strategy. The goal is not to - avoid life— it’s to protect consistency. That means we prioritise barrier stability and inflammation control first, then introduce corrective work in a way your skin can tolerate without rebound. In practical terms, we’ll often advise avoiding deliberate heat loading around active treatment phases (very hot rooms/saunas, prolonged direct sun/heat exposure), because heat can keep pigment pathways and vascular reactivity switched on for longer.
How to protect your skin in the real world
A smart protection plan still starts with daily broad-spectrum UV protection (this is non-negotiable because UV remains the biggest driver of photoaging). Then we add sensible heat/IR risk management: seek shade when possible, wear protective clothing/hats when outdoors for extended periods, and avoid repeated overheating of facial skin if you’re inflammation-prone. Alongside that, evidence reviews on protection beyond UV highlight the role of topical antioxidants as a supportive layer, because oxidative stress is one of the key pathways implicated in IR-A effects.
The bottom line
Infrared isn’t the headline villain in skin ageing — UV still dominates — but IR-A and heat can meaningfully compound oxidative stress and inflammatory signalling, particularly in sensitive, redness-prone, or pigmentation-prone skin. When we manage IR/heat exposure intelligently and keep the barrier stable, results from professional treatments and corrective skincare tend to land faster and hold longer.
